Turbo Receiver With Dual-Loop Dual-List Update for Inter-Cell Interference Mitigation in Heterogeneous Networks

Inter-cell interference (ICI) may considerably degrade the detection performance of receivers in heterogeneous networks (HetNets). To increase the spectrum efficiency per area, the cell ranges of small cells may be expanded, making the ICI problem more severe. Furthermore, to pursue higher data rate, spatial multiplexing is often applied, incurring inter-antenna interference (IAI). This paper presents a turbo receiver with a dual-loop dual-list update (TRDDU) structure that efficiently detects data signal deteriorated by both ICI and IAI. The proposed lists maintained several likely data vectors and interference vectors, facilitating the receiver to more efficiently determine the most-likely solution. In addition, a dual-loop update algorithm was proposed to enhance the iteration efficiency. Moreover, two design techniques were proposed to reduce the detection complexity. Simulation results showed that the error rate performance of TRDDU is close to that of a receiver in the ICI-free scenario. The complexity needed by TRDDU is only 3.5% that of the receiver that considers all possible interference vectors. In addition, the TRDDU complexity is only approximately 1.56 times that of a successive-interference-cancellation-based receiver. Finally, an over-the-air experiment was conducted to validate the effectiveness of the proposed TRDDU, and the results demonstrated the feasibility of this receiver in the field.